Clad only in hooded sweatshirts, high school students in Manitowoc try to stay warm in sub-zero temperatures on Monday.

Written by

Gannett Wisconsin Media and USA TODAY

Some of the coldest air in four years has plunged into the Midwest and will spread to the 50 million people living in the Northeast by Tuesday, where temperatures are forecast to remain below freezing throughout the day.

Frigid temperatures and gusty winds brought wind chill values down to 25 to 50 degrees below zero this morning across the upper Midwest.

The wind chill bottomed out at -51 in Langdon, N.D., early Monday morning, thanks to a temperature of -22 degrees combined with a wind of 17 mph, reports Weather Underground meteorologist Jeff Masters.Frigid Forecast ...